The hot source is spliced to the black, fan wire and the black wire running to the dimmer. At the other end, the black cable wire is spliced to one of the hot dimmer wires, it doesn’t matter which one. The other dimmer wire is spliced to the red wire in the switch box which is spliced to the blue, light wire at the other end.
This diagram illustrates the wiring for a circuit with gfci receptacles followed by a light and switch. By connecting the switch to the load terminals on the gfci, the light is protected against ground faults as well.
This diagram illustrates the wiring for a Cooper gfci/switch combo device wired to protect a garbage disposal. With this arrangement a receptacle, switch and disposal are protected with the ground fault breaker built into the device.
Here the source is at the fan/light and a switch loop runs to the wall switch. The source is wired directly to the fan and spliced through to the switch. With this arrangement the light is controlled with the switch and the fan is hardwired for pull-chain control.